(1) Field of the invention
U.S. Class 380—Cryptography:—The study of secret information storage or communication.
U.S. Class 178—Telegraphy:—Means for transmitting messages, the elements of the messages being selected or composed at will, according to a prearranged code
(2) Description of the Related Art including information disclosed under 37 CFR 1.97 and CFR 1.98:                Thornwall, U.S. Pat. No. 4,675,477; “Electronic Devices Providing Automatic Permutations of a Vigenere Square”        Helen Fouche Gaines, “Cryptanalysis—A Study of ciphers and their solutions”        